Assessing Titania Pigment Distribution in Water-Based Coatings by Image Analysis of Ion Beam Milled Sections

By applying various image analysis methods, the distribution of titania pigments in water-based paint films is assessed in this work. Cross-sections of paint films containing titania are prepared using triple ion beam milling, and the milled cross-sections are imaged using scanning electron microscopy. The obtained morphology of the paint films with known difference in pigment distribution is then determined and quantified by means of image analysis. It is found that the inter-particle distance which is calculated by determining the distance between each individual particle can serve as good differentiator for assessing the quality of pigment distribution. Furthermore, a comparison is made between 2D (triple ion beam milling) and 3D (focused ion beam with slice and view) imaging methods on the same sample. The 2D method, with its ease of use, short experimental time and artefact free imaging, gives better results in the system studied in this work.